Folding rafter square



Jan. 13, 1953 Filed July 24, 1951 Jan. '13, 1953 E. PEN Kl-:R 2,624,947

FOLDING RAFTER SQUARE Filed July 24, 1951 2 SHEETS-SHEET 2 BY .2@ Aoe/vey Patented Jan. 13, 1953 UNITED STATES PATENT OFFICE FOLING RAFTER SQUARE Ernest Penker, Flushing, N. Y., assignor to Etched Products Corporation, Long Island City, N. Y., a corporation of New York Application July 24, 1951, Serial N0. 238,242

6 Claims.

This invention relates to carpenters folding squares, such as a roofing or rafter square and, more particularly, to an improved, more accurate, and more rugged folding square.

Folding square constructions have been proposed to provide for compact packing of the square in a carpenters tool chest, the rigid type of square, particularly in the larger sizes, being difticult to pack and usually having one leg projecting. However, these constructions have had numerous disadvantages, such as complicated interconnections, lack of accuracy, and liability to derangement. In particular, prior locking arrangements for holding the arms of the square in properly oriented relation have either been unduly complicated or else unsatisfactory in operation.

The present invention is directed to an improved folding square eliminating the disadvantages of prior constructions. To this end, the invention square includes a pair of pivotally interrelated arms, one of which is substantially rectilinear and the other of which is L-shaped in plan. The short leg of the L is reduced in thickness throughout its length, forming shoulder on the longer leg aligned with the inner edge of.

the short leg. The rectilinear arm of the square is correspondingly reduced in thickness at its inner end for a distance equal to the length of the short leg of the L.

The resultant shoulder on the straight arm is undercut to receive a projecting lip on the end the reduced thickness sections in constant engagement with each other.

The outer end of the short leg of the angular arm has a notch which, in the extended posin tion of the square, receives a sliding finger on the straight arm, the nger and notch cooperatively maintaining the arms in correct angular relation. Near its inner end, the inner edge of the straight arm has a recess, preferably arcuate, which receives a headed element set into the surface of the angular arm and projecting somewhat beyond the aforementioned shoulder thereon. The recess and headed element rigidly maintain the reduced thickness arm portions in firm bearing engagement in the open position of the square.

For an understanding of the invention principles, reference is made to the following detailed description of a typical embodiment thereof as illustrated in the accompanying drawing.

In the drawing:

Figs. 1 and 2 are top plan views of the invention square in the open and the folded positions, respectively;

Figs. 3 and 4 are bottom plan views of the open and folded square, respectively;

Fig. 5 is a sectional view on the line 5-5 of Fig. 3; and

Fig. 6 is a sectional view on the line 6 6 of Fig. 2.

Fig. 7 is a sectional view on line 1-1 of Fig. 5.

Referring to the drawing, the square includes a substantially straight arm Il) and an angular L-shape arm 2t, both preferably of a suitable relatively rigid metal. Arm 20 has a relatively short leg 25 and a relatively long leg 26. Leg 25 is reduced to a thickness substantially one-half that of leg 26, and its outer edge has a projecting lip 2|, the outer edge being arcuate at one end 22. This outer edge also has a notch 23 for a purpose to be described.

A shoulder 24 is formed by the junction of legs 25 and 26, being aligned with the inner edge of leg 25. A rivet, or the like, 21 headed as at 27 is afxed through leg 2B adjacent shoulder 24 so that its head partly extends over leg 25, the head 21 being spaced from the surface of leg 25. The two arms, Ill and 20, are pivotally interconnected 'by a fixed position bearing, such as a rivet I5,

which is located near the inner corner of the square and connecting arm I0 to leg 25. Bearing I5 is preferably hardened to reduce wear thereon.

The inner end of arm I0 is reduced in thickness as at II for a length corresponding to leg 25. This reduction forms a rectilinear shoulder I2 which is undercut, to receive lip 2| on leg 25. The reduced thickness portion I I of arm Ill is always in surface engagement with leg 25. The relative dimensions and locations of shoulders I2 and 24 and rivet 2l are such that, in the open position of the square, shoulder 24 is ush with the inner side I3 of arm I0, and shoulder I2 is flush with the outer edge of leg 25. This flush engagement is facilitated by the arcuate portion 22 of such outer edge, which allows clearance of the arms during pivoting thereof.

The inner side I3 of arm I0 has an arcuate recess I4 of a depth equal to the thickness of the head 21 of rivet 21, so that head 21', engaging in recess I4, assures rm maintenance of the surface-to-surface contact of arm Il) and leg 25 when the square is open.

Recess 23 in the outer edge of leg 25 receives the end I6 of a keeper or lock bar I6 in the open position of the square. Bar I6 is longitudinally slidable in an elongated recess Il in the bottom surface of arm I0. A slot I8 connects recess Il to the top surface of arm I0, which surface has a recessed ledge I9 bounding slot I8. A rivet 30 headed as at 30' is connected to bar I6, having a Shank extending through slot I8, the rivet head 30 riding on ledge I9. Keeper I6 is easily engaged and disengaged relative to recess 23 by a simple sliding movement, and serves t lock arms I0 and 2i) accurately at a right angle when the square is open.

The described square is compact and rugged and its arms are maintained in firm surface engagement by the keeper bar arrangement and rivet 21. Keepel` I6 also assures accurate perpendicularity of the arms when the square is open. The hardened bearing rivet I greatly assists the maintenance of rigid intel-relation of the arms.

While a specific embodiment of the invention has been shown and described in detail to illustrate the invention principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

l. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other armbeing substantially L-shaped in plan, and one leg of the L and the end portion of the straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the arms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a pivot bearing interconnecting the reduced thickness portions of the two arms, an end of the outer edge of at least one of the reduced thickness portions being arcuate, the shoulder on the angular arm b-eing aligned with the inner edge of such one leg and having iiush engagement with one side of the straight arm when the square is open, the other` shoulder having ilush engagement with the outer edge of such one leg when the square is open, each arm having means at its shoulder closely overlying a portion of the cooperating edge of the other arm when the square is open, and a keeper bar mounted on one arm adjacent the shoulder f thereof for longitudinal sliding movement to and from projected relation to the shoulder, the cooperating edge of the other arm having a recess therein to receive said keeper bar in the open position of the square.

2. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other arm being substantially L-shaped in plan, and one leg of the L and the end portion of the straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the arms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a pivot bearing interconnecting the reduced thickness portions of the two arms, the shoulder on the angular arm being aligned with the inner edge of such one leg and having flush engagement with one side of the straight arm when the square is open, the other shoulder having flush engagement with the outer edge of such one leg When the square is open, a headed element secured through one arm at the shoulder thereof and projecting partly from the shoulder in spaced relation to the reduced thickness portion of such one arm, the other arm having a recess in its edge arranged to fittingly receive such headed element in the open position of the square, and a keeper bar mounted on one arm adjacent the shoulder thereof for longitudinal sliding movement to and from projected relation to the shoulder, the cooperating edge of the other arm having a recess therein to receive said keeper bar in the open position of the square.

3. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other arm being substantially L-shape in plan. and one leg of the L and the end portion of the straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the arms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a pivot bearing interconnecting the reduced thickness portions of the two arms, the shoulder on the angular arm being aligned with the inner edge of such one leg and having flush engagement with one side of the straight arm when the square is open, the other shoulder having flush engagement with the outer edge of such one leg when the square is open, a headed element secured through one arm at the shoulder thereof and projecting partly from the shoulder in spaced relation to the reduced thickness portion of such one arm, the other arm having a recess in its edge arranged to ttingly receive such headed element in the open position of the square and the shoulder of the other arm being undercut to receive a lip projecting from the cooperating edge of such one arm, and a keeper bar mounted on one arm adjacent the shoulder thereof for longitudinal sliding movement to and from projected relation t0 the shoulder, the cooperating edge of the other arm having a recess therein to receive said keeper bar in the open position of the square.

4. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other arm being substantially L-shape in plan, and one leg of the L and the end portion of the Straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the arms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a hardened pivot bearing interconnecting the reduced thickness portions of the two arms, an end of the outer edge of the leg of the L 0f reduced thickness being arcuate the shoulder on the angular arm being aligned with the inner edge of such one leg and having flush engagement with one side of the straight arm when the square is open, the other shoulder having flush engagement with the outer edge of such one leg when the square is open, each arm having means at its shoulder closely overlying a portion of the cooperating edge of the other arm when the square is open, and a keeper bar mounted on one arm adjacent the shoulder thereof for longitudinal sliding movement to and from projected relation to the shoulder, the cooperating edge of the other arm having a recess therein to receive said keeper bar in the open position of the square.

5. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other arm being substantially L-shape in plan, and one leg of the L and the end p-ortion of the straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the arms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a pivot bearing interconnecting the reduced thickness portions of the tWo arms, the shoulder on the angular arm being aligned with the inner edge of such one leg and having flush engagement with one side of the straight arm when the square is open, the other shoulder having flush engagement with the outer edge of such one leg when the square is open, a headed element secured through the angular arm at the shoulder thereof and projecting partly from the shoulder in spaced relation to the reduced thickness portion of such angular arm, the straight arm having a recess in its edge arranged to ttingly receive such headed element in the open position of the square, and a keeper bar mounted on the straight arm adjacent the shoulder thereof for longitudinal sliding movement to and from projected relation to the shoulder, the outer edge of such one leg of the other arm having a recess therein to receive said keeper bar in the open position of the square, said keeper bar being slidable in an elongated recess in one surface of the straight arm and being flush with such one surface.

6. A foldable square comprising, in combination, a pair of pivotally interconnected arms, one of said arms being substantially straight and the other arm being substantially L-shape in plan, and one leg of the L and the end portion of the straight arm being substantially one-half the thickness of the main portions of the arm and having surface bearing engagement in all positions of the Iarms, such reduced thickness portions forming shoulders at their junctions with the main portions of the arms, a pivot bearing interconnecting the reduced thickness portions of the two arms, the shoulder on the angular arm being aligned with the inner edge of such one leg and having flush engagement with one side of the straight arm When the square is open, the other shoulder having flush engagement With the outer edge of such one leg when the square is open, a headed element secured through angular arm at the shoulder thereof and projecting partly from the shoulder in spaced relation to the reduced thickness portion of such angular arm, the straight arm having a recess in its edge arranged to fittingly receive such headed element in the open position of the square and the shoulder of the straight arm being undercut to receive a lip projecting from the cooperating edge of such one leg, and a keeper bar mounted on the straight arm adjacent the shoulder thereof for longitu dinal sliding movement to and from projected relation to the shoulder, the outer edge of such one leg of the other arm having a recess therein to receive said keeper bar in the open position of the square, said keeper bar being slidable in `an elongated recess in one surface of the straight arm and being flush with such one surface.

ERNEST PENKER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 563,370 Goldsberry July 7, 1896 944,541 Graig Dec. 28, 1909 952,177 Barker Mar. 15, 1910 1,668,290 Stevens May 1, 1928 

